Coupling of Rayleigh-Wood anomalies and the circular Bragg phenomenon in slanted chiral sculptured thin films

CATMAS – Computational and Theoretical Materials Sciences Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812, USA

Corresponding authors: fuw101@psu.edu axl4@psu.edu mes17@psu.edu

Received: 2 May 2002
Revised: 9 August 2002
Accepted: 9 August 2002
Published online: 25 October 2002

Abstract

Slanted chiral sculptured thin films (STFs) are introduced as nano-engineered materials that are effectively periodic in two orthogonal directions. Their periodicities normal and parallel to the substrate plane are related by a slant angle. A coupled wave theory is formulated and implemented for the planewave response of a slanted chiral STF of finite thickness. Numerical results show that the nonspecular remittances and the Rayleigh-Wood anomalies due to periodicity parallel to the substrate plane are tightly coupled to the specular nature of the circular Bragg phenomenon displayed due to periodicity normal to the substrate plane. In the Bragg regime, the left- and the right-circularly polarized components of the incident plane wave are redirected in non-trivially different directions. The potential of slanted chiral STFs as narrowband circular polarization beamsplitters is established.